The present invention relates to the use of N-alkanoyl compounds as activators for hydrogen peroxide and for inorganic peroxo compounds which are sources of hydrogen peroxide and capable of releasing it in aqueous phase, wherein the activation consists in the formation of an organic percarboxylic acid. In a further aspect, the present invention relates to these new activators and their use in washing, bleaching and cleaning agents as well as disinfectant compositions containing inorganic peroxo compounds.
Inorganic peroxygen compounds are used as oxidizing agents in bleaching, washing and cleaning agents and disinfectants in order to improve the action of such agents. Hydrogen peroxide and such substances as release hydrogen peroxide in aqueous solution, such as perborates and percarbonates, in particular are used as peroxygen compounds. The action of the inorganic peroxygen compounds depends on the pH value and considerably on the temperature. While at temperatures above about 80.degree. C. a good effect is achieved, it is known that at lower temperatures, especially at or below about 60.degree. C. or at or below about 40.degree. C., the co-utilization of so-called activators is required with the named inorganic peroxygen compounds. The activators are principally N-acyl or O-acyl compounds. In aqueous phase percarboxylic acids, which display a good washing, cleaning, bleaching and disinfecting action in the low-temperature range also, are formed out of H.sub.2 O.sub.2 or H.sub.2 O.sub.2 -releasing inorganic peroxygen compounds and the activators.
Among the N-acyl compounds, numerous classes of substances have been proposed in the past as activators, including N,N,N',N'-tetraacetylethylenediamine (TAED), N,N,N',N'-tetraacetylglycoluril (TAGU), N-(C.sub.1 to C.sub.4)- or N-(C.sub.6 to C.sub.10)-alkanoylhydantoins (DE-C 19 49 561 and U.S. Pat. No. 4,412,934 respectively), N,N'-(C.sub.1 to C.sub.8)-alkanoyl-2,5-diketopiperazines (DE-A 20 38 106) and N-(C.sub.1 to C.sub.4)-alkanoylsuccinimide (DE-C 19 49 561 and GB-B 855735). Despite this variety of proposed activators, of the N-acyl compounds previously disclosed essentially only TAED has been successful on the market.
From U.S. Pat. No. 4,412,934 bleaching agent compositions are known that contain as the activator, substances of the formula R--CO--L, wherein R is an alkyl group with 5 to 18 C atoms, whose longest chain R--CO has 6 to 10 carbon atoms, and the conjugate acid of the leaving group L has a pK.sub.a value of 6 to 13. Among the leaving groups, many groups linked to R--CO via oxygen but also a few via amide nitrogen are disclosed, including the N-hydantoinyl group, but not the N-succinyl group. Preferred leaving groups are phenol derivatives; the group R preferably represents linear (C.sub.5 to C.sub.9)-alkyl chains; the activator nonanoyloxybenzenesulphonate (NOBS) is particularly preferred. NOBS is a very active activator, contained in conventional commercial bleaching agent compositions, whose bleaching effect exceeds that of TAED.
In view of the growing demand for washing, bleaching and cleaning agents and disinfectants for the low-temperature range, there is an interest in further activators based on N-acyl compounds, which come up to or exceed the property characteristics of NOBS. The activators should as far as possible be accessible from easily available raw materials and be readily biodegradable.